Why are cab units preferred for passenger service?

[TinGoat]

One more thing comes to mind...

Actually two...

First, many of the later [More modern] Cab Units are actually Cowl Units. They have the same structure as Hood Units with heavy frames, but with full width hoods.

This leads to the second thought...

Crew Movements.

Modern Freight Trains have an Engineer and a Brakeman who generally stay in the Cab while the train is in motion.

Passenger Trains have an Engineer, Brakeman, Fireman and Conductor and more... They need to move freely from one end of the train to the other and with some protection from the elements, under the Cowl while the train is moving...